The present invention relates to particular types of alkylbenzene sulfonate surfactant mixtures adapted for laundry and cleaning product use by controlling compositional parameters, especially a 2/3-phenyl index, a 2-methyl-2-phenyl index and linearity, as well as to improved detergent and cleaning products containing these surfactant mixtures, to alkylbenzene precursors for the surfactant mixtures, and to methods of making the precursors as well as the surfactant mixtures. The present compositions are especially useful for fabric laundering.
Historically, highly branched alkylbenzene sulfonate surfactants, such as those based on tetrapropylene, known as xe2x80x9cABSxe2x80x9d or xe2x80x9cTPBSxe2x80x9d, were used in detergents. However, these were found to be very poorly biodegradable. A long period followed of improving manufacturing processes for alkylbenzene sulfonates, making them as linear as practically possible, hence the acronym xe2x80x9cLASxe2x80x9d. The overwhelming part of a large art of linear alkylbenzene sulfonate surfactant manufacture is directed to this objective. However, linear alkylbenzene sulfonates are not without limitations; for example, they would be more desirable if improved for hard water cleaning and/or cold water cleaning properties. They can often fail to produce good cleaning results, for example when formulated with nonphosphate builders and/or when used in hard water areas.
As a result of the limitations of the alkylbenzene sulfonates, consumer cleaning formulations have often needed to include a higher level of co-surfactants, builders, and other additives than would have been needed given a superior alkylbenzene sulfonate. Yet another currently unresolved problem in alkylbenzene sulfonate manufacture is to make more effective use of current LAB feedstock. It would be highly desirable, both from a performance point of view and from an economic point of view, to better utilize certain desirable types of branched hydrocarbons.
Accordingly there exists a substantial unment need for further improvements in alkylbenzene sulfonate surfactant mixtures. Improved alkylbenzene sulfonates should provide one or more of the following advantages: superior cleaning, hardness tolerance, biodegradability and cost.
It has now surprisingly been found that there exist certain alkylbenzene sulfonate surfactant mixtures, hereinafter xe2x80x9cenhanced alkylbenzene sulfonate surfactant mixturesxe2x80x9d which offer one or more, and even several of the above-outlined advantages. The discovery of these mixtures solves important problems of the kind described in the background.
More specifically, it has now surprisingly been found for that the alkylbenzene sulfonate surfactant mixtures of the present invention provide superior cleaning performance, cost advantage, along with good biodegradability as compared to conventional alkylbenzene sulfonate surfactant mixtures. In most cases, standard environmental tests, such as the previously described Modified SCAS, are sufficient in determining acceptable surfactant biodegradability. It has additionally been discovered that the alkylbenzene sulfonate surfactant mixtures of the present invention afford a further improved performance and biodegradation profile over the prior art. The present invention achieves the further improved profile by optimizing key compositional parameters, including, but not limited to, the 2/3-phenyl index, the 2-methyl-2-phenyl index and overall linearity. These features provide superior cleaning performance to those who practice the invention, while providing globally acceptable protection of the environment during and following such practice.
In a first aspect of the present invention, an enhanced alkylbenzene sulfonate surfactant mixture comprising:
(a) from about 60% to about 25% by weight of a mixture of enhanced alkylbenzene sulfonates having formula (I): 
xe2x80x83wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen, said L having two methyl termini and said L having no substituents other than A, R1 and R2; and wherein said mixture of enhanced alkylbenzene sulfonates contains two or more of said enhanced alkylbenzene sulfonates differing in molecular weight of the anion of said formula (I) and wherein said mixture of enhanced alkylbenzene sulfonates has
a sum of carbon atoms in R1, L and R2 of from 9 to 15
an average aliphatic carbon content of from about 10.0 to about 14.0 carbon atoms; M is a cation or cation mixture, M having a valence q of the value of from 1 to 2; a and b are integers selected such that said enhanced alkylbenzene sulfonates are electroneutral; R1 is C1-C3 alkyl; R2 is selected from H and C1-C3 alkyl provided that in at least about 0.5 to 1.0 mole fraction of said enhanced alkylbenzene sulfonates, R2 is H; A is a benzene moiety or any other aromatic that would exhibit the same characteristics as the aforementioned benzene moiety under the above-described conditions; and
(b) from about 40% to about 75% by weight of a mixture of modified unsubstituted alkylbenzene sulfonates having formula (II): 
xe2x80x83wherein a, b, M, A and q are as defined hereinbefore and Y is a linear unsubstituted aliphatic moiety having no substitution other than A, consisting of carbon and hydrogen having two methyl termini, and wherein said Y has a sum of carbon atoms of from 9 to 15 and said Y has an average aliphatic carbon content of from about 10.0 to about 14.0; and wherein said modified unsubstituted alkylbenzene sulfonate surfactant mixture is further characterized by a 2/3-phenyl index of from about 275 to about 10,000, is provided.
In a second aspect of the present invention, a process for making an alkylbenzene sulfonate surfactant mixture comprising the steps of: (I) alkylating benzene with an alkylating mixture; (II) sulfonating the product of (I); and (optionally, but preferably) (III) neutralizing the product of (II); wherein said alkylating mixture comprises: (a) 1% to about 99%, by weight of methyl substituted C9-C15 monoolefins, said methyl substituted monoolefins having structures identical with those of the methyl substituted monoolefins formed by dehydrogenating methyl substituted paraffins of formula R1LR2 wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and containing two terminal methyls; R1 is C1 to C3 alkyl; and R2 is selected from H and C1 to C3 alkyl; and (b) from about 0.1% to about 85%, by weight of C9-Cl5 linear aliphatic olefins; wherein said alkylating mixture contains said methyl substituted C9-C20 monoolefins having at least two different carbon numbers in said C9-C20 range, and has a mean carbon content of from about 9.0 to about 15.0 carbon atoms; and wherein said components (a) and (b) are at a weight ratio of at least about 15:85, is provided.
In another aspect of the present invention, an alkylbenzene sulfonate surfactant mixture made by the process described above is provided.
In still another aspect of the present invention, detergent compositions, especially laundry detergent compositions, comprising the enhanced alkylbenzene sulfonate surfactant mixture of the present invention are provided. Such detergent compositions generally contain an amount of the enhanced alkylbenzene sulfonate surfactant mixture useful in cleaning fabrics, and amounts of laundry detergent-specific adjuncts which distinguish the preferred compositions herein from compositions used in non-laundry detergent fields.
The invention, on the other hand, is not intended to encompass any wholly conventional alkylbenzene sulfonate compositions or the derivative detergent compositions, such as those based exclusively on linear alkylbenzene sulfonates made by any process, or exclusively on known unacceptably branched alkylbenzene sulfonates such as ABS or TPBS.
In yet another aspect of the present invention, an enhanced alkylbenzene mixture is provided. This alkylbenzene mixture is useful for making the enhanced alkylbenzene sulfonate surfactant mixtures of the first and second embodiments, and comprises: (a) from about 60% to about 25% by weight of a mixture of enhanced alkylbenzenes having formula (I): 
wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and having two methyl termini, and wherein said mixture of enhanced alkylbenzenes contains two or more compounds of said formula (I) differing in molecular weight and wherein said mixture of enhanced alkylbenzenes is characterized by a sum of carbon atoms in R1, R2 and L of from 9 to 15; and an average aliphatic carbon content (i.e., excluding A), based on the sum of R1, L and R2, of from about 10.0 to about 14.0 carbon atoms; and further, wherein L has no substituents other than A, R1 and R2; R1 is C1-C3 alkyl (preferably C1-C2 alkyl, more preferably methyl); R2 is selected from H and C1-C3 alkyl provided that in at least about 0.5 mole fraction of said enhanced alkylbenzene, R2 is H); A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than L); and (b) from about 40% to about 75% by weight of a mixture of modified unsubstituted alkylbenzenes having formula (II): 
wherein A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than L) and Y is a linear aliphatic moiety having no substituents other than A consisting of carbon and hydrogen having two methyl termini, and wherein Y has from 9 to 15 carbon atoms in total and said mixture of modified unsubstituted alkylbenzenes has an average aliphatic carbon content (i.e., carbon content excluding A) of from about 10.0 to about 14.0 carbon atoms; and wherein said modified unsubstituted alkylbenzene mixture is further characterized by a 2/3-phenyl index of from about 275 to about 10,000, and a 2-methyl-2-phenyl index of less than about 0.3.
In accordance with other embodiments of the present invention, there are encompassed herein a number of alternate and less preferred embodiments, such as those in which there is blending of the enhanced alkylbenzene sulfonate surfactant mixture of the invention with one or more other alkylbenzene sulfonate surfactants. In practical terms, such blending is usually encompassed before sulfonation and detergent formulation, but the outcome is a surfactant mixture or detergent composition containing a blend of the enhanced alkylbenzene sulfonate surfactant with other, known, alkylbenzene sulfonates. Such alternate embodiments of the invention nonlimitingly include those termed herein as xe2x80x9cmedium 2/3-phenyl surfactant mixturesxe2x80x9d. Such surfactant mixtures essentially contain useful amounts of the enhanced alkylbenzene sulfonate surfactant, along with other known alkylbenzene sulfonates subject to specific provisions of the 2/3-phenyl index of the overall composition. Such compositions include: a medium 2/3-phenyl surfactant mixture consisting essentially of: from 1% to about 60% by weight of a first alkylbenzene sulfonate surfactant, wherein said first alkylbenzene sulfonate surfactant is an enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment; and b) from 40% to about 99% by weight of a second alkylbenzene sulfonate surfactant, wherein said second alkylbenzene sulfonate surfactant is an alkylbenzene sulfonate surfactant mixture other than said enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment, and wherein said second alkylbenzene sulfonate surfactant has a 2/3-phenyl index of from about 75 to about 160 (typically said second alkylbenzene sulfonate surfactant is a commercial C10-C14 linear alkylbenzene sulfonate surfactant, e.g., DETAL(copyright) process LAS or HF process LAS though in general any commercial linear (LAS) or branched (ABS, TPBS) type can be used); provided that said medium 2/3-phenyl surfactant mixture has a 2/3-phenyl index of from about 160 to about 275. Of course, it is equally possible within the spirit and scope of the invention to prepare any blend of the enhanced alkylbenzene sulfonate surfactant mixture of the invention with any known commercial linear or branched alkylbenzene sulfonate surfactant.
Preferred cleaning composition embodiments also contain specific cleaning adjuncts defined hereafter. Moreover, the invention encompasses less preferred but sometimes useful embodiments for their normal purposes, such as the addition of useful hydrotrope precursors and/or hydrotropes, such as C1-C8 alkylbenzenes, more typically toluenes, cumenes, xylenes, naphthalenes, or the sulfonated derivatives of any such materials, minor amounts of any other materials, such as tribranched alkylbenzene sulfonate surfactants, dialkylbenzenes and their derivatives, dialkyl tetralins, wetting agents, processing aids, and the like. It will be understood that, with the exception of hydrotropes, it will not be usual practice in the present invention to include any such materials. Likewise it will be understood that such materials, if and when they interfere with analytical methods, will not be included in samples of compositions used for analytical purposes.
The abovementioned embodiments and other aspects of the present invention are more fully described and exemplified in the detailed description hereinafter.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
First Embodiment
A. Enhanced Alkylbenzene Sulfonate Surfactant Mixtures
The present invention encompasses an enhanced alkylbenzene sulfonate surfactant mixture comprising (preferably, consisting essentially of): (a) from about 60% to about 25% by weight, preferably from about 55% to about 35%, more preferably from about 50% to about 40% of a mixture of enhanced alkylbenzene sulfonates having formula (I): 
wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen, said L having two methyl termini and said L having no substituents other than A, R1 and R2; and wherein said mixture of enhanced alkylbenzene sulfonates contains two or more (preferably at least three, optionally more) of said enhanced alkylbenzene sulfonates differing in molecular weight of the anion of said formula (I) and wherein said mixture of enhanced alkylbenzene sulfonates has a sum of carbon atoms in R1, L and R2 of from 9 to 15 (preferably from 10 to 14); an average aliphatic carbon content (i.e., based on R1, L and R2 and excluding A) of from about 10.0 to about 14.0 carbon atoms (preferably from about 10.5 to about 12.5, more preferably from about 11.0 to about 12.0); M is a cation or cation mixture (preferably selected from H, Na, K, Ca, Mg and mixtures thereof, more preferably selected from H, Na, K and mixtures thereof, more preferably still, selected from H, Na, and mixtures thereof) having a valence q (typically from 1 to 2, preferably 1); a and b are integers selected such that said enhanced alkylbenzene sulfonates are electroneutral (a is typically from 1 to 2, preferably 1, b is 1); R1 is C1-C3 alkyl (preferably C1-C2 alkyl, more preferably methyl); R2 is selected from H and C1-C3 alkyl (preferably H and C1-C2 alkyl, more preferably H and methyl, more preferably H and methyl provided that in at least about 0.5, more preferably 0.7, more preferably 0.9 to 1.0 mole fraction of said enhanced alkylbenzene sulfonates, R2 is H); A is a benzene moiety (typically A is the moiety xe2x80x94C6H4xe2x80x94, with the SO3 moiety of Formula (I) in para-position to the L moiety, though in some proportion, usually no more than about 5%, preferably from 0 to 5% by weight, the SO3 moiety is ortho- to L); and (b) from about 40% to about 75% by weight, preferably from about 45% to about 65%, more preferably from about 50% to about 60% of a mixture of modified unsubstituted alkylbenzene sulfonates having formula (II): 
wherein a, b, M, A and q are as defined hereinbefore and Y is a linear aliphatic moiety having no substituents other than A consisting of carbon and hydrogen having two methyl termini, and wherein said Y has a sum of carbon atoms of from 9 to 15, preferably from 10 to 14, and said Y has an average aliphatic carbon content of from about 10.0 to about 14.0 (preferably from about 10.5 to about 12.5, more preferably 11.0 to about 12.0 carbon atoms); and wherein said modified unsubstituted alkylbenzene sulfonate is further characterized by a 2/3-phenyl index of from about 275 to about 10,000, preferably from about 300 to about 5,000, more preferably from about 325 to about 2,500.
A preferred modified unsubstituted alkylbenzene sulfonate has M selected from H, Na, K and mixtures thereof, said a=1, said b=1, said q=1, and said enhanced alkylbenzene sulfonate surfactant mixture has a 2-methyl-2-phenyl index of less than about 0.3, preferably less than about 0.2, more preferably from 0 to about 0.1.
Such an enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment can be made as the product of a process using as alkylation catalyst a zeolite selected from mordenite, offretite and H-ZSM-12 in at least partially acidic form, preferably an acidic mordenite. Moreover, any alkylation catalyst that exhibits the same or similar characteristics as those of mordenite, under the same or similar conditions, may be employed in the process of making the enhanced alkylbenzene surfactant mixture according to the first embodiment. For instance, certain forms of zeolite beta that exhibit the same or similar characteristics as those of mordenite under the same or similar conditions may be employed as an alternative to mordenite, but are not highly preferred. Embodiments described in terms of their making, as well as suitable catalysts, are all further detailed hereinafter.
Another preferred enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment of the invention consists essentially of said mixture of enhanced alkylbenzene sulfonates and modified unsubstituted alkylbenzene sulfonates, wherein said 2-methyl-2-phenyl index of said enhanced alkylbenzene sulfonate surfactant mixture is less than about 0.1, and wherein in said mixture of enhanced and modified unsubstituted alkylbenzene sulfonates, said average aliphatic carbon content is from about 11.0 to about 12.0 carbon atoms; said R1 is methyl; said R2 is selected from H and methyl provided that in at least about 0.7 mole fraction of said enhanced alkylbenzene sulfonates R2 is H; and wherein said sum of carbon atoms in R1, L and R2 is from 10 to 14; and further wherein in said mixture of modified unsubstituted alkylbenzene sulfonates, said Y has a sum of carbon atoms of from 10 to 14 carbon atoms, said average aliphatic carbon content of said modified unsubstituted alkylbenzene sulfonates is from about 11.0 to about 12.0 carbon atoms, and said M is a monovalent cation or cation mixture selected from H, Na and mixtures thereof.
Definitions
Methyl Termini
The terms xe2x80x9cmethyl terminixe2x80x9d and/or xe2x80x9cterminal methylxe2x80x9d mean the carbon atoms that are the terminal carbon atoms in alkyl moieties, that is L, and/or Y of formula (I) and formula (II) respectively are always bonded to three hydrogen atoms. That is, they will form a CH3xe2x80x94 group. To better explain this, the structure below shows the two terminal methyl groups in an alkylbenzene sulfonate. 
The term xe2x80x9cABxe2x80x9d herein when used without further qualification is an abbreviation for xe2x80x9calkylbenzenexe2x80x9d of the so-called xe2x80x9chardxe2x80x9d or nonbiodegradable type, which on sulfonation forms xe2x80x9cABSxe2x80x9d. The term xe2x80x9cLABxe2x80x9d herein is an abbreviation for xe2x80x9clinear alkylbenzenexe2x80x9d of the current commercial, more biodegradable type, which on sulfonation forms linear alkylbenzene sulfonate, or xe2x80x9cLASxe2x80x9d. The term xe2x80x9cMLASxe2x80x9d herein is an abbreviation for the enhanced alkylbenzene sulfonate surfactant mixtures of the invention.
Impurities
The enhanced alkylbenzene sulfonate surfactant mixtures herein are preferably substantially free from impurities selected from tribranched impurities, dialkyl tetralin impurities and mixtures thereof. By xe2x80x9csubstantially freexe2x80x9d it is meant that the amounts of such impurities are insufficient to contribute positively or negatively to the cleaning effectiveness of the composition. Typically there is less than about 5%, preferably less than about 1%, more preferably about 0.1% or less of the impurity, that is typically no one of the impurities with practical analytical detection limits.
Illustrative Structures
The better to illustrate the possible complexity of the enhanced alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions, structures (a) to (v) below are illustrative of some of the many preferred compounds of formula (I). These are only a few of hundreds of possible preferred structures that make up the bulk of the composition, and should not be taken as limiting of the invention. 
Structures (w) and (x) nonlimitingly illustrate less preferred compounds of Formula (I) which can be present, at lower levels than the above-illustrated preferred types of structures, in the enhanced alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions. 
Structures (y), (z), and (aa) nonlimitingly illustrate compounds broadly within Formula (I) that are not preferred but which can be present in the enhanced alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions. 
Structure (bb) is illustrative of a tri-branched structure not within Formula (I), but that can be present as an impurity.
Structures (cc), (dd) and (ee) are illustrative of structures not within Formula (I), but that can be present as impurities.
First Embodiment
B. Enhanced Alkylbenzene Sulfonate Surfactant Mixtures Defined on the Basis of their Preparation
Preferably the enhanced alkylbenzene sulfonate surfactant mixtures herein are the product of sulfonating the corresponding enhanced alkylbenzene mixtures, wherein the enhanced alkylbenzene is produced by alkylating benzene with a substituted olefin, and more particularly the lightly substituted types described in more detail hereinafter, over an acidic mordenite-type catalyst, or other suitable catalyst as defined elsewhere herein.
In outline, enhanced alkylbenzene sulfonate surfactant mixtures herein can be made by the steps of:
(I) alkylating benzene with an alkylating mixture;
(II) sulfonating the product of (I); and (optionally but very preferably)
(III) neutralizing the product of (II).
Provided that suitable alkylation catalysts and process conditions as taught herein are used, the product of step (I) is an enhanced alkylbenzene mixture in accordance with the invention. Provided that sulfonation is conducted under conditions generally known and reapplicable from LAS manufacture, see for example the literature references cited herein, the product of step (II) is an enhanced alkylbenzene sulfonic acid mixture in accordance with the invention. Provided that neutralization step (III) is conducted as generally taught herein, the product of step (III) is an enhanced alkylbenzene sulfonate surfactant mixture in accordance with the invention. Since neutralization can be incomplete, mixtures of the acid and neutralized forms of the present enhanced alkylbenzene sulfonate surfactant mixtures in all proportions, e.g., from about 1000:1 to 1:1000 by weight are also part of the present invention. Preferably, said alkylating mixture contains said branched C9-C20 monoolefins having at least two different carbon numbers in said C9-C20 range, and has a mean carbon content of from about 9.0 to about 15.0 carbon atoms; and wherein said components (a) and (b) are at a weight ratio of at least about 15:85.
Preferred enhanced alkylbenzene sulfonate surfactant mixtures herein comprise the product of a process comprising the steps of: (I) alkylating benzene with an alkylating mixture; (II) sulfonating the product of (I); and (optionally but very preferably) (III) neutralizing the product of (II); wherein said alkylating mixture comprises: (a) from about 1% to about 99.9%, by weight of methyl-substituted C9-C15 (preferably C10-C14) monoolefins, said substituted monoolefins having structures identical with those of the substituted monoolefins formed by dehydrogenating substituted paraffins of formula R1 LR2 wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and containing two terminal methyls; R1 is C1 to C3 alkyl; and R2 is selected from H and C1 to C3 alkyl; and (b) from about 0.1% to about 85%, by weight of C9-C15 (preferably C10-C14) linear aliphatic olefins; wherein said alkylating mixture contains said methyl-substituted C9-C15 monoolefins having at least two different carbon numbers in said C9-C15 range, and has a mean carbon content of from about 9.0 to about 15.0 carbon atoms (preferably from about 10.0 to about 14.0, more preferably from about 10.5 to about 12.5, more preferably still from about 11.0 to about 12.0); and wherein said components (a) and (b) are at a weight ratio of at least about 15:85 (preferably having methyl-substituted component (a) and modified unsubstituted component (b) in a performance and biodegradation optimum ratio, for example from 25% to 60% of (a) and 40% to 75% of (b), more preferably 35% to 55% of (a) and 45% to 65% of (b), more preferably still 40% to 50% of (a) and 50% to 60% of (b), wherein these percentages by weight exclude any other materials, for example diluent hydrocarbons, that may be present in the process). Said monoolefins (a) or (b) may be internal monoolefins, alpha-olefins, and/or mixtures thereof.
may be diluted with certain materials selected from paraffins and inert, non-paraffinic solvents. Further, the resultant olefin/paraffin mixture may be obtained via the dehydrogenation of a paraffin mixture obtained from kerosene feed stock via a molecular sieving unit designed to isolate a mixture, consisting mainly of both linear and monomethyl branched paraffins from cyclic and dimethyl branched paraffins. Said mixture is blended, if needed, to achieve a linear content of 40% to 75%.
In yet another preferred embodiment, the invention encompasses an enhanced alkylbenzene sulfonate surfactant mixture prepared in accordance with the above-outlined steps wherein said alkylating mixture may be obtained via any one of the following:
1) Dimerization of short chain olefin mixtures inside a molecular sieve
2) Oligomerization of short chain olefin mixtures inside a molecular sieve
3) Product of cracking long-chain hydrocarbon waxes under conditions to obtain a mainly mono methyl branched olefin product;
4) Dehydrogenation of a paraffin mixture obtained from a gas to liquids (GTL) plant.
Other enhanced alkylbenzene sulfonate surfactant mixtures herein are made by the above-outlined processes wherein in step (I), said alkylation is performed in the presence of an alkylation catalyst, said alkylation catalyst is an intermediate acidity solid porous alkylation catalyst, and step (II) comprises removal of components other than monoalkylbenzene prior to contacting the product of step (I) with sulfonating agent.
Also encompassed is the enhanced alkylbenzene sulfonate surfactant mixture according to the above-defined processes wherein said alkylation catalyst is other than a member selected from the group consisting of HF, AlCl3, sulfuric acid and mixtures thereof. Such is the case when the alkylation catalyst is selected from the group consisting of non-fluoridated acidic mordenite-type catalyst, fluoridated acidic mordenite-type catalyst and mixtures thereof.
The processes are tolerant of variation, for example conventional steps can be added before, in parallel with, or after the outlined steps (I), (II) and (III). This is especially the case for accommodating the use of hydrotropes or their precursors. Thus the invention encompasses an enhanced alkylbenzene sulfonate surfactant mixture according to the above-outlined processes wherein a hydrotrope, hydrotrope precursor, or mixtures thereof is added after step (I); or the hydrotrope, hydrotrope precursor or mixtures thereof is added during or after step (II) and prior to step (m); or a hydrotrope can be added during or after step
In certain cases, compositions herein can also be prepared by blending. Thus, the invention includes a detergent composition using an enhanced alkylbenzene sulfonate surfactant blend according to the first embodiment wherein said enhanced alkylbenzene sulfonate surfactant mixture is prepared by a process comprising a step selected from: (i) blending a mixture of enhanced and modified unsubstituted alkylbenzene sulfonate surfactants having a 2/3-phenyl index of 500 to 700 with an alkylbenzene sulfonate surfactant mixture having a 2/3-phenyl index of 75 to 160 and (ii) blending a mixture of methyl-substituted and modified unsubstituted alkylbenzenes having a 2/3-phenyl index of 500 to 700 with an alkylbenzene mixture having a 2/3-phenyl index of 75 to 160 and sulfonating said blend.
Sulfonation and Workup or Neutralization (Steps II/III)
In general, sulfonation of the enhanced alkylbenzene mixture in the instant process can be accomplished using any of the well-known sulfonation systems, including those described in xe2x80x9cDetergent Manufacture Including Zeolite Builders and other New Materialsxe2x80x9d, Ed. Sittig., Noyes Data Corp., 1979, as well as in Vol. 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. This work provides access to a great deal of literature describing various processes and process steps, not only sulfonation but also dehydrogenation, alkylation, alkylbenzene distillation and the like. Common sulfonation systems useful herein include sulfuric acid, chlorosulfonic acid, oleum, sulfur trioxide and the like. Sulfur trioxide/air is especially preferred. Details of sulfonation using a suitable air/sulfur trioxide mixture are provided in U.S. Pat. No. 3,427,342, Chemithon. Sulfonation processes are further extensively described in xe2x80x9cSulfonation Technology in the Detergent Industryxe2x80x9d, W. H. de Groot, Kluwer Academic Publishers, Boston, 1991.
Any convenient workup steps may be used in the present process. Common practice is to neutralize after sulfonation with any suitable alkali. Thus the neutralization step can be conducted using alkali selected from sodium, potassium, ammonium, magnesium and substituted ammonium alkalis and mixtures thereof. Potassium can assist solubility, magnesium can promote soft water performance and substituted ammonium can be helpful for formulating specialty variations of the instant surfactants. The invention encompasses any of these derivative forms of the enhanced alkylbenzene sulfonate surfactant mixtures as produced by the present process and their use in consumer product compositions.
Alternately the acid form of the present surfactants can be added directly to acidic cleaning products, or can be mixed with cleaning ingredients and then neutralized.
The hydrotropes or hydrotrope precursors useful herein can in general be selected from any suitable hydrotrope or hydrotrope precursor, including lower alkyl (C1-C8) aromatics and their sulfonic acids and sulfonate salts, but are more typically based on a sulfonic acid or sodium sulfonate salt of toluene, cumene, xylene, napthalene or mixtures thereof. The hydrotrope precursors are selected from any suitable hydrotrope precursor, typically toluene, cumene, xylene, napthalene or mixtures thereof. A hydrotrope precursor is a compound that during step (III), namely the sulfonation step, is converted into a hydrotrope.
Moreover, it is contemplated that the alkylation xe2x80x9cstepxe2x80x9d (I) herein can be xe2x80x9cstagedxe2x80x9d so that two or more reactors operating under different conditions in the defined ranges may be useful. By operating a plurality of such reactors, it is possible to allow for material with less preferred 2-methyl-2-phenyl index to be initially formed and, surprisingly, to convert such material into material with a more preferred 2-methyl-2-phenyl index.
In terms of sulfonating agent selection, the invention encompasses an enhanced alkylbenzene sulfonate surfactant mixture wherein step (II) is performed using a sulfonating agent selected from the group consisting of sulfur trioxide, sulfur trioxide/air mixtures, and sulfuric acid (including oleum). Chlorosulfonic acid or other known sulfonating agents, while less commercially relevant, are also useful and are included for use in the invention.
Although in general, neutralization step (III) can be carried out with any suitable alkali, the invention includes an enhanced alkylbenzene sulfonate surfactant mixture wherein said step (III) is performed using a basic salt, said basic salt having a cation selected from the group consisting of alkali metal, alkaline earth metal, ammonium, substituted ammonium, and mixtures thereof and an anion selected from hydroxide, oxide, carbonate, silicate, phosphate, and mixtures thereof. Preferred basic salt is selected from the group consisting of sodium hydroxide, sodium silicate, potassium hydroxide, potassium silicate, magnesium hydroxide, ammonium hydroxide, and mixtures thereof.
Alkylation Catalyst
To secure the enhanced alkylbenzene sulfonate surfactant mixtures of the invention, the present invention uses a particularly defined alkylation catalyst. Said alkylation catalyst is an intermediate acidity solid porous alkylation catalyst defined in detail hereinafter. Particularly preferred alkylation catalysts comprise at least partially dealuminized acidic non-fluoridated mordenites, at least partially dealuminized acidic fluoridated mordenites, and mixtures thereof. In additional embodiments, a preferred alkylation catalyst is that which exhibits the same or similar characteristics as the mordenite catalyst, under the same or similar conditions. One such catalyst may stem from the group consisting of zeolite beta catalysts, of certain and specific form, but is not preferred.
Numerous alkylation catalysts are unsuitable for making the present enhanced alkylbenzene mixtures and enhanced alkylbenzene sulfonate surfactant mixtures. Unsuitable alkylation catalysts include any of: sulfuric acid, aluminum chloride, and HF. Also unsuitable are non-acidic calcium mordenite, and many others. Other catalysts, such as the DETAL(copyright) process catalysts of UOP are also unsuitable, at least in their current commercial executions.
In contrast, suitable alkylation catalysts herein are selected from shape-selective moderately acidic alkylation catalysts, preferably zeolitic. The zeolite catalyst used for the alkylation step (I) is preferably selected from the group consisting of mordenite, HZSM-12, NES and offretite, any of these being in at least partially acidic form. Mixtures can be used and the catalysts can be combined with binders etc. More preferably, the zeolite is substantially in acid form and is contained in a catalyst pellet comprising a conventional binder and further wherein said catalyst pellet comprises at least about 1%, more preferably at least 5%, more typically from 50% to about 90%, of said zeolite.
More generally, a suitable alkylation catalyst is typically at least partially crystalline, more preferably substantially crystalline not including binders or other materials used to form catalyst pellets, aggregates or composites. Moreover the catalyst is typically at least partially acidic. Fully exchanged Ca-form mordenite, for example, is unsuitable whereas H-form mordenite is suitable.
EP 466,558 describes an acidic mordenite type alkylation catalyst also of possible use herein having overall Si/Al atomic ratio of 15-85 (15-60), Na weight content is less than 1000 ppm (preferably less than 250 ppm), and there is a low or zero content of extra-network Al species; the elementary mesh volume as defined in EP 466,558 is below 2,760 nm3.
U.S. Pat. No. 5,057,472 is likewise useful for preparing alkylation catalysts herein and relates to concurrent dealumination and ion-exchange of an acid-stable Na ion-containing zeolite, preferably mordenite, effected by contact of the zeolite with a 0.5-3 (preferably 1-2.5) M HNO3 solution containing sufficient NH4NO3 to fully exchange the Na+ ions for NH4+ and H+ ions. The resulting zeolites can have a SiO2:Al2O3 ratio of 15:1 to 26:1, preferably 17:1 to 23:1, and are preferably calcined to at least partially convert the NH4+/H+ form to the H+ form. Optionally, though not necessarily particularly desirable in the present invention, the catalyst can contain a Group VIII metal (and optionally also an inorganic oxide) together with the calcined zeolite of ""472.
Another acidic mordenite catalyst useful for the alkylation step herein is disclosed in U.S. Pat. No. 4,861,935 which relates to a hydrogen form of mordenite incorporated with alumina, the composition having a surface area of at least 580 m2/g. Other acidic mordenite catalysts useful for the alkylation step herein include those described in U.S. Pat. Nos. 5,243,116 and 5,198,595. Yet another alkylation catalyst useful herein is described in U.S. Pat. No. 5,175,135 which is an acid mordenite zeolite having a silica/alumina molar ratio of at least 50:1, a Symmetry Index of at least 1.0 as determined by X-ray diffraction analysis, and a porosity such that the total pore volume is in the range from about 0.18 cc/g to about 0.45 cc/g and the ratio of the combined meso- and macropore-volume to the total pore volume is from about 0.25 to about 0.75.
Particularly preferred alkylation catalysts herein include the acidic mordenite catalysts Zeocat(trademark) FM-8/25H available from Zeochem; CBV 90 A available from Zeolyst International, and LZM-8 available from UOP Chemical Catalysts as well as fluoridated versions of the above commercial catalysts. Fluoridated mordenites can be prepared by a number of ways. A method of providing a particularly useful fluoridated mordenite is described in U.S. Pat. No. 5,777,187. The invention encompasses preferred embodiments in which the mordenites are fluoridated, but also has other preferred embodiments in which the mordenites are non-fluoridated.
Most generally, any alkylation catalyst may be used herein provided that the alkylation catalyst can (a) accommodate methyl-substituted olefins as described elsewhere herein into the smallest pore diameter of said catalyst and (b) selectively alkylate benzene with said substituted olefins and optionally mixtures thereof with linear olefins. Acceptable selectivity is in accordance with a 2/3-Phenyl index of about 275 to about 10,000 as defined herein.
In other terms, the catalyst selections herein are made in part with the intention of minimizing internal alkylbenzene formation (e.g., 4-phenyl, 5-phenyl . . . ). The formulators contributing to the present invention have unexpectedly discovered that control of internal alkylbenzene sulfonate isomers in the present inventive surfactant mixtures in conjunction with introduction of limited methyl branching is very helpful for improving their performance. The present invention connects this discovery to discoveries of the synthesis chemists in the present invention, who have determined how to control internal isomer content while providing limited methyl branching in the enhanced alkylbenzene sulfonate surfactant mixtures in accordance with the formulators"" prescriptions.
The extent to which internal isomer content needs to be controlled can vary depending on the consumer product application and on whether outright best performance or a balance of performance and cost is required. In absolute terms, the amount of internal isomer such as internal alkylbenzene isomer is preferably always kept below 25% by weight, but for best results, from 0 to 10%, preferably less than about 5% by weight. xe2x80x9cInternal alkylbenzenexe2x80x9d isomers as defined herein include alkylbenzenes having phenyl attachment to an aliphatic chain in the 4, 5, 6 or 7 position.
Without intending to be limited by theory, there are two reasons for which it is believed that the preferred alkylation catalysts are the above-described shape selective zeolitic type catalysts, especially mordenites. The first reason is to provide the selectivity of formation of preferred compounds such as substituted and unsubstituted 2-phenyl and 3-phenylalkylbenzenes. This selectivity is measured by the 2/3-phenyl index. The second reason is to control the amount of quaternary alkylbenzenes and thus quaternary alkylbenzene sulfonates.
Results with alkylation catalysts such as HF can give quite high levels of quaternary alkylbenzenes as shown in the literature (see J. Org. Chem. Vol. 37, No. 25, 1972). This contrasts with the surprising discovery as part of the present invention that one can attain low levels of quaternary alkylbenzenes in catalyzed reactions of benzene with substituted olefins, as characterized by 2-methyl-2-phenyl index. In practice, some isomerization of the enhanced alkylbenzenes may occur during alkylation, i.e. the ratio of enhanced alkylbenzenes to modified unsubstituted alkylbenzenes may vary.
Second Embodiment
Detergent Compositions
The present invention has numerous detergent composition embodiments, including the detergent composition comprising: (a) from about 1% to about 50%, preferably from about 2% to about 30%, by weight of enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment, wherein said enhanced alkylbenzene sulfonate surfactant mixture has a 2-methyl-2-phenyl index of less than about 0.3, preferably of from 0 to 0.2, more preferably no more than about 0.1, more preferably still, no more than about 0.05; (b) from about 0.000001% to about 10%, preferably from about 0.01% to about 2%, of a member selected from the group consisting of optical brighteners, dyes, photobleaches, hydrophobic bleach activators and transition metal bleach catalysts, preferably at least two of said member components, more preferably at least two of said member components including an optical brightener as one of the member components; (c) from 0.1% to about 40% by weight (preferably not more than about 30%) of surfactants selected from the group consisting of cationic surfactants, nonionic surfactants, anionic surfactants, and amine oxide surfactants (more preferably at least one cationic surfactant is present at a level of from about 0.2% to about 5% by weight, or at least one nonionic surfactant is present at a level of from about 0.5% to about 25% by weight, or at least one alkyl sulfate surfactant or alkyl(polyalkoxy)sulfate surfactant is present at a level of from about 0.5% to about 25% by weight); and (d) from about 10% to about 99% of conventional cleaning adjuncts (other than any of (a)-(c)); provided that when said detergent composition comprises any alkylbenzene sulfonate surfactant other than said enhanced alkylbenzene sulfonate surfactant mixture (for example as a result of blending into the detergent composition one or more commercial, especially linear, typically linear C10-C14, alkylbenzene sulfonate surfactants), said detergent composition is further characterized by an overall 2/3-phenyl index of at least about 200, preferably at least about 250, more preferably at least about 350, more preferably still, at least about 500, wherein said overall 2/3-phenyl index is determined by measuring 2/3-phenyl index, as defined herein, on a blend of said enhanced alkylbenzene sulfonate surfactant mixture and said any other alkylbenzene sulfonate to be added to said detergent composition, said blend, for purposes of measurement, being prepared from aliquots of said enhanced alkylbenzene sulfonate surfactant mixture and said other alkylbenzene sulfonate not yet exposed to any other of said components of the detergent composition; and further provided that when said detergent composition comprises any alkylbenzene sulfonate surfactant other than said enhanced alkylbenzene sulfonate surfactant mixture (for example as a result of blending into the detergent composition one or more commercial, especially linear, typically linear C10-C14, alkylbenzene sulfonate surfactants), said detergent composition is further characterized by an overall 2-methyl-2-phenyl index of less than about 0.3, preferably from 0 to 0.2, more preferably no more than about 0.1, more preferably still, no more than about 0.05, wherein said overall 2-methyl-2-phenyl index is to be determined by measuring 2-methyl-2-phenyl index, as defined herein, on a blend of said enhanced alkylbenzene sulfonate surfactant mixture and any other alkylbenzene sulfonate to be added to said detergent composition, said blend, for purposes of measurement, being prepared from aliquots of said enhanced alkylbenzene sulfonate surfactant mixture and said other alkylbenzene sulfonate not yet exposed to any other of said components of the detergent composition.
These provisions may appear somewhat unusual, however they are consistent with the spirit and scope of the present invention, which encompasses a number of economical but less preferred approaches in terms of overall cleaning performance, such as blending of the enhanced alkylbenzene sulfonate surfactants with conventional linear alkylbenzene sulfonate surfactants either during synthesis or during formulation into the detergent composition. Moreover, as is well known to practitioners of detergent analysis, a number of detergent adjuncts (paramagnetic materials such as certain transition metal bleach catalysts, for example, and sometimes even water) are capable of interfering with methods for determining the parameters of alkylbenzene sulfonate surfactant mixtures as described hereinafter. Hence wherever possible, analysis should be conducted on dry materials before mixing them into the detergent compositions.
Numerous variations of the present detergent compositions are useful. Such variations include:
the detergent composition, which is substantially free from alkylbenzene sulfonate surfactants other than said, enhanced alkylbenzene sulfonate surfactant mixture;
the detergent composition which comprises, in said component (c), at least about 0.1%, preferably no more than about 10%, more preferably no more than about 5%, more preferably still, no more than about 1%, of a commercial C10-C14 linear alkylbenzene sulfonate surfactant;
said conventional cleaning adjunct which comprises from about 0.1% to about 5% of a cationic surfactant, such as one selected from substituted and unsubstituted C8-C16 alkyl ammonium salts;
the detergent composition which comprises, in said component (c), at least about 0.1%, preferably no more than about 10%, more preferably no more than about 5%, more preferably still, no more than about 1%, of a commercial highly branched alkylbenzene sulfonate surfactant. (e.g., TPBS or tetrapropylbenzene sulfonate);
the detergent composition which comprises, in said component (c), a nonionic surfactant at a level of from about 0.5% to about 25% by weight of said detergent composition, and wherein said nonionic surfactant is a polyalkoxylated alcohol in capped or non-capped form having:xe2x80x94a hydrophobic group selected from linear C10-C16 alkyl, mid-chain C1-C3 branched C10-C16 alkyl, guerbet branched C10-C16 alkyl, and mixtures thereof andxe2x80x94a hydrophilic group selected from 1-15 ethoxylates, 1-15 propoxylates 1-15 butoxylates and mixtures thereof, in capped or uncapped form. (when uncapped, there is also present a terminal primary xe2x80x94OH moiety and when capped, there is also present a terminal moiety of the form xe2x80x94OR wherein R is a C1-C6 hydrocarbyl moiety, optionally comprising a primary or, preferably when present, a secondary alcohol.);
the detergent composition which comprises, in said component (c), an alkyl sulfate surfactant at a level of from about 0.5% to about 25% by weight of said detergent composition, wherein said alkyl sulfate surfactant has a hydrophobic group selected from linear C10-C18 alkyl, mid-chain C1-C3 branched C10-C18 alkyl, guerbet branched C10-C18 alkyl, and mixtures thereof and a cation selected from Na, K and mixtures thereof;
the detergent composition which comprises, in said component (c), an alkyl(polyalkoxy)sulfate surfactant at a level of from about 0.5% to about 25% by weight of said detergent composition, wherein said alkyl(polyalkoxy)sulfate surfactant hasxe2x80x94a hydrophobic group selected from linear C10-C16 alkyl, mid-chain C1-C3 branched C10-C16 alkyl, guerbet branched C10-C16 alkyl, and mixtures thereof andxe2x80x94a (polyalkoxy)sulfate hydrophilic group selected from 1-15 polyethoxysulfate, 1-15 polypropoxysulfate, 1-15 polybutoxysulfate, 1-15 mixed poly(ethoxy/propoxy/butoxy)sulfates, and mixtures thereof, in capped or uncapped form; andxe2x80x94a cation selected from Na, K and mixtures thereof;
the detergent composition having the form of a heavy-duty liquid detergent;
the detergent composition having the form of a syndet laundry bar;
the detergent composition having the form of a heavy-duty granule;
the detergent composition having the form of a heavy-duty granule and wherein said conventional cleaning adjunct (d) comprises from about 10% to about 50% by weight of said detergent composition of a nonphosphate builder;
the detergent composition having the form of a heavy-duty granule and wherein said conventional cleaning adjunct (d) comprises from about 10% to about 50% by weight of said detergent composition of a phosphate builder; and
the detergent composition having the form of a heavy-duty granule and wherein said conventional cleaning adjunct (d) comprises as said phosphate builder a member selected from the group consisting of sodium tripolyphosphate.
Further the present invention includes a detergent composition comprising (preferably consisting essentially of): (a) from about 0.1% to about 95%, by weight (preferably from about 0.5% to about 50%, more preferably from about 1%, preferably at least 2%, more preferably at least 4%, more preferably at least 6%, more preferably still at least 8% to about 35%) of enhanced alkylbenzene sulfonate surfactant mixture according to the invention; (b) from about 0.00001% to about 99.9% (preferably from about 5% to about 98%, more preferably from about 50% to about 95%) of conventional cleaning adjuncts other than surfactants; and (c) from 0% to about 50%, by weight (in some preferred embodiments, 0%, and in others preferably from about 0.1% to about 30%, more typically from about 0.2% to about 10%), of a surfactant other than said enhanced alkylbenzene sulfonate surfactant mixture; provided that when said detergent composition comprises any other alkylbenzene sulfonate than the alkylbenzene sulfonate of said enhanced alkylbenzene sulfonate surfactant mixture, said enhanced alkylbenzene sulfonate surfactant mixture and said other alkylbenzene sulfonate, as a mixture, have an overall 2/3-phenyl index of from about 275 to 10,000, preferably from about 300 to about 5,000, more preferably from about 325 to about 2,5000.
In another detergent embodiment, there is encompassed herein a detergent composition comprising: (a) from about 0.1% to about 95%, by weight (preferably from about 0.5% to about 50%, more preferably from about 1% to about 35%) of enhanced alkylbenzene sulfonate surfactant mixture of the invention; (b) from about 0.00001% to about 99.9% (preferably from about 5% to about 98%, more preferably from about 50% to about 95%) of conventional cleaning adjuncts other than surfactants; and (c) from 0.1% to about 50%, by weight (preferably from about 0.1% to about 35%, more typically from about 1% to about 15%) of surfactants other than alkylbenzene sulfonates (preferably, one or more surfactants selected from the group consisting of cationic surfactants, anionic surfactants, and anionic surfactants other than alkylbenzene sulfonates, more preferably wherein a cationic surfactant is present, said cationic surfactant is at a level of from about 0.2% to about 5%).
The invention also includes a detergent composition consisting essentially of: (a) from about 1% to about 50% (preferably from about 1% to about 35%), by weight of enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment of the invention; (b) from about 0.00001% to about 99.9% (preferably from about 5% to about 98%, more preferably from about 50% to about 95%) of conventional cleaning adjuncts other than surfactants; and (c) from 0.1% to about 50% (preferably from about 0.1% to about 35%, more typically from about 1% to about 15%) by weight of surfactants other than alkylbenzene sulfonates (preferably, one or more surfactants selected from the group consisting of cationic surfactants, anionic surfactants, and anionic surfactants other than alkylbenzene sulfonates, more preferably wherein a cationic surfactant is present at a level of from about 0.2% to about 5%); and (d) from 0.1% to about 95% water.
Likewise part of the invention is a detergent composition consisting essentially of: (a) from about 0.1% to about 95%, by weight of enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment; and (b) from about 0.00001% to about 99.9% of conventional cleaning adjuncts other than surfactants.
More generally, detergent compositions can include the enhanced alkylbenzene sulfonate surfactant mixtures together with any conventional cleaning adjunct other than surfactants, such as those wherein the adjunct is selected from the group consisting of builders, detersive enzymes, bleaching systems, brighteners, at least partially water-soluble or water dispersible polymers, abrasives, bactericides, tarnish inhibitors, dyes, solvents, hydrotropes, perfumes, thickeners, antioxidants, processing aids, suds boosters, suds suppressors, buffers, anti-fungal agents, mildew control agents, insect repellents, anti-corrosive aids, chelants and mixtures thereof.
The compositions in accordance with the invention can take a variety of physical forms including granular, gel, tablet, bar and liquid forms. The compositions include the so-called concentrated granular detergent compositions adapted to be added to a washing machine by means of a dispensing device placed in the machine drum with the soiled fabric load.
The mean particle size of the components of granular compositions in accordance with the invention should preferably be such that no more that 5% of particles are greater than 1.7 mm in diameter and not more than 5% of particles are less than 0.15 mm in diameter.
The term mean particle size as defined herein is calculated by sieving a sample of the composition into a number of fractions (typically 5 fractions) on a series of Tyler sieves. The weight fractions thereby obtained are plotted against the aperture size of the sieves. The mean particle size is taken to be the aperture size through which 50% by weight of the sample would pass.
Certain preferred granular detergent compositions in accordance with the present invention are the high-density types, now common in the marketplace; these typically have a bulk density of at least 600 g/liter, more preferably from 650 g/liter to 1200 g/liter.
High Density Detergent Composition Processes
Various means and equipment are available to prepare high density (i.e., greater than about 550, preferably greater than about 650, grams/liter or xe2x80x9cg/lxe2x80x9d), high solubility, free flowing, granular detergent compositions according to the present invention. Current commercial practice in the field employs spray-drying towers to manufacture granular laundry detergents that often have a density less than about 500 g/l. In this procedure, an aqueous slurry of various heat-stable ingredients in the final detergent composition are formed into homogeneous granules by passage through a spray-drying tower, using conventional techniques, at temperatures of about 175xc2x0 C. to about 225xc2x0 C. However, if spray drying is used as part of the overall process herein, additional or alternative process steps as described hereinafter must be used to obtain the level of density (i.e.,  greater than 650 g/l) required by modern compact, low dosage detergent products.
For example, spray-dried granules from a tower can be densified further by loading a liquid such as water or a nonionic surfactant into the pores of the granules and/or subjecting them to one or more high-speed mixer/densifiers. A suitable high speed mixer/densifier for this process is a device marketed under the tradename xe2x80x9cLxc3x6dige CB 30xe2x80x9d or xe2x80x9cLxc3x6dige CB 30 Recyclerxe2x80x9d which comprises a static cylindrical mixing drum having a central rotating shaft with mixing/cutting blades mounted thereon. In use, the ingredients for the detergent composition are introduced into the drum and the shaft/blade assembly is rotated at speeds in the range of 100-2500 rpm to provide thorough mixing/densification. See Jacobs et al, U.S. Pat. No. 5,149,455, issued Sep. 22, 1992, and U.S. Pat. No. 5,565,422, issued Oct. 15, 1996 to Del Greco et al. Other such apparatus includes the devices marketed under the tradename xe2x80x9cShugi Granulatorxe2x80x9d and under the tradename xe2x80x9cDrais K-TTP 80).
Another process step which can be used to densify further spray-dried granules involves treating the spray-dried granules in a moderate speed mixer/densifier. Equipment such as that marketed under the tradename xe2x80x9cLxc3x6dige KMxe2x80x9d (Series 300 or 600) or xe2x80x9cLxc3x6dige Ploughsharexe2x80x9d mixer/densifiers are suitable for this process step. Such equipment is typically operated at 40-160 rpm. The residence time of the detergent ingredients in the moderate speed mixer/densifier is from about 0.1 to 12 minutes conveniently measured by dividing the steady state mixer/densifier weight by the throughput (e.g., Kg/hr). Other useful equipment includes the device which is available under the tradename xe2x80x9cDrais K-T 160xe2x80x9d. This process step which employs a moderate speed mixer/densifier (e.g. Lxc3x6dige KM) can be used by itself or sequentially with the aforementioned high-speed mixer/densifier (e.g. Lxc3x6idige CB) to achieve the desired density. Other types of granules manufacturing apparatus useful herein include the apparatus disclosed in U.S. Pat. No. 2,306,898, to G. L. Heller, Dec. 29, 1942.
While it may be more suitable to use the high-speed mixer/densifier followed by the low speed mixer/densifier, the reverse sequential mixer/densifier configuration also can be used. One or a combination of various parameters including residence times in the mixer/densifiers, operating temperatures of the equipment, temperature and/or composition of the granules, the use of adjunct ingredients such as liquid binders and flow aids, can be used to optimize densification of the spray-dried granules in the process of the invention. By way of example, see the processes in Appel et al, U.S. Pat. No. 5,133,924, issued Jul. 28, 1992; Delwel et al, U.S. Pat. No. 4,637,891, issued Jan. 20, 1987; Kruse et al, U.S. Pat. No. 4,726,908, issued Feb. 23, 1988; and, Bortolotti et al, U.S. Pat. No. 5,160,657, issued Nov. 3, 1992.
In those situations in which particularly heat sensitive or highly volatile detergent ingredients are to be incorporated into the final detergent composition, processes which do not include spray drying towers are preferred. The formulator can eliminate the spray-drying step by feeding, in either a continuous or batch mode, starting detergent ingredients directly into mixing equipment that is commercially available. One particularly preferred embodiment involves charging a surfactant paste and an anhydrous material into a high-speed mixer/densifier (e.g. Lxc3x6dige CB) followed by a moderate speed mixer/densifier (e.g. Lxc3x6dige KM) to form high-density detergent agglomerates. See Capeci et al, U.S. Pat. No. 5,366,652, issued Nov. 22, 1994 and Capeci et al, U.S. Pat. No. 5,486,303, issued Jan. 23, 1996. Optionally, the liquid/solids ratio of the starting detergent ingredients in such a process can be selected to obtain high density agglomerates that are more free flowing and crisp. See Capeci et al, U.S. Pat. No. 5,565,137, issued Oct. 15, 1996.
Optionally, the process may include one or more recycle streams of undersized particles produced by the process that are fed back to the mixer/densifiers for further agglomeration or build-up. The oversized particles produced by this process can be sent to grinding apparatus and then fed back to the mixing/densifying equipment. These additional recycle process steps facilitate build-up agglomeration of the starting detergent ingredients resulting in a finished composition having a uniform distribution of the desired particle size (400-700 microns) and density ( greater than 550 g/l). See Capeci et al, U.S. Pat. No. 5,516,448, issued May 14, 1996 and Capeci et al, U.S. Pat. No. 5,489,392, issued Feb. 6, 1996. Other suitable processes which do not call for the use of spray-drying towers are described by Bollier et al, U.S. Pat. No. 4,828,721, issued May 9, 1989; Beerse et al, U.S. Pat. No. 5,108,646, issued Apr. 28, 1992; and, Jolicoeur, U.S. Pat. No. 5,178,798, issued Jan. 12, 1993.
In yet another embodiment, a high-density detergent composition using a fluidized bed mixer. In this process, the various ingredients of the finished composition are combined in an aqueous slurry (typically 80% solids content) and sprayed into a fluidized bed to provide the finished detergent granules. Prior to the fluidized bed, this process can optionally include the step of mixing the slurry using the aforementioned Lxc3x6dige CB mixer/densifier or a xe2x80x9cFlexomix 160xe2x80x9d mixer/densifier, available from Shugi. Fluidized bed or moving beds of the type available under the tradename xe2x80x9cEscher Wyssxe2x80x9d can be used in such processes.
Another suitable process which can be used herein involves feeding a liquid acid precursor of an anionic surfactant, an alkaline inorganic material (e.g. sodium carbonate) and optionally other detergent ingredients into a high speed mixer/densifier so as to form particles containing a partially or totally neutralized anionic surfactant salt and the other starting detergent ingredients. Optionally, the contents in the high-speed mixer/densifier can be sent to a moderate speed mixer/densifier (e.g. Lxc3x6dige KM) for further mixing resulting in the finished high-density detergent composition. See Appel et al, U.S. Pat. No. 5,164,108, issued Nov. 17, 1992.
Optionally, high density detergent compositions according to the invention can be produced by blending conventional or densified spray-dried detergent granules with detergent agglomerates in various proportions (e.g. a 60:40 weight ratio of granules to agglomerates) produced by one or a combination of the processes discussed herein. See U.S. Pat. No. 5,569,645, issued Oct. 29, 1996 to Dinniwell et al. Additional adjunct ingredients such as enzymes, perfumes, brighteners and the like can be sprayed or admixed with the agglomerates, granules or mixtures thereof produced by the processes discussed herein.
Related to the detergent composition embodiments are methods of their use, such as a method comprising treating a fabric with the detergent composition of the invention. Such methods are part of the present invention. Machine laundry methods herein typically comprise treating soiled laundry with an aqueous wash solution in a washing machine having dissolved or dispensed therein an effective amount of a machine laundry detergent composition in accord with the invention. By an effective amount of the detergent composition it is here meant from 40 g to 300 g of product dissolved or dispersed in a wash solution of volume from 5 to 65 liters, as are typical product dosages and wash solution volumes commonly employed in conventional machine laundry methods.
As noted, surfactants are used herein in detergent compositions, preferably in combination with other detersive surfactants, at levels which are effective for achieving at least a directional improvement in cleaning performance. In the context of a fabric laundry composition, such xe2x80x9cusage levelsxe2x80x9d can vary widely, depending not only on the type and severity of the soils and stains, but also on the wash water temperature, the volume of wash water and the type of washing machine.
In a preferred use aspect a dispensing device is employed in the washing method. The dispensing device is charged with the detergent product, and is used to introduce the product directly into the drum of the washing machine before the commencement of the wash cycle. Its volume capacity should be such as to be able to contain sufficient detergent product as would normally be used in the washing method.
Once the washing machine has been loaded with laundry the dispensing device containing the detergent product is placed inside the drum. At the commencement of the wash cycle of the washing machine water is introduced into the drum and the drum periodically rotates. The design of the dispensing device should be such that it permits containment of the dry detergent product but then allows release of this product during the wash cycle in response to its agitation as the drum rotates and also as a result of its contact with the wash water.
Alternatively, the dispensing device may be a flexible container, such as a bag or pouch. The bag may be of fibrous construction coated with a water impermeable protective material so as to retain the contents, such as is disclosed in European published Pat. No. Application No. 0018678. Alternatively it may be formed of a water-insoluble synthetic polymeric material provided with an edge seal or closure designed to rupture in aqueous media as disclosed in European published Patent Application Nos. 0011500, 0011501, 0011502, and 0011968. A convenient form of water frangible closure comprises a water-soluble adhesive disposed along and sealing one edge of a pouch formed of a water impermeable polymeric film such as polyethylene or polypropylene.
Third Embodiment
Precursor Alkylbenzene Mixtures
The present invention also includes an enhanced alkylbenzene mixture comprising (preferably consisting essentially of): (a) from about 60% to about 25%, preferably from about 55% to about 35%, more preferably from about 50% to 40%, by weight of a mixture of enhanced alkylbenzenes having formula (I): 
wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and having two methyl termini, and wherein said mixture of enhanced alkylbenzenes contains two or more compounds of said formula (I) differing in molecular weight and wherein said mixture of enhanced alkylbenzenes is characterized by a sum of carbon atoms in R1, R2 and L of from 9 to 15, preferably from 10 to 14; and an average aliphatic carbon content (i.e., excluding A), based on the sum of R1, L and R2, of from about 10.0 to about 14.0, preferably from about 10.5 to about 12.5, more preferably from about 11.0 to about 12.0 carbon atoms; and further, wherein L has no substituents other than A, R1 and R2; R1 is C1-C3 alkyl (preferably C1-C2 alkyl, more preferably methyl); R2 is selected from H and C1-C3 alkyl (preferably H and C1-C2 alkyl, more preferably H and methyl provided that in at least about 0.5, more preferably 0.7, more preferably 0.9 to 1.0 mole fraction of said enhanced alkylbenzenes, R2 is H); A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than L); and (b) from about 40% to about 75%, preferably from about 45% to about 65%, more preferably from about 50% to 60%, by weight of a mixture of modified unsubstituted alkylbenzenes having formula (II): 
wherein A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than L) and Y is a linear aliphatic moiety with no substituents other than A consisting of carbon and hydrogen having two methyl termini, and wherein Y has from 9 to 15 carbon atoms in total (preferably from 10 to 14) and said mixture of modified unsubstituted alkylbenzenes has an average aliphatic carbon content (i.e., carbon content excluding A) of from about 10.0 to about 14.0 carbon atoms, preferably from about 10.5 to about 12.5 carbon atoms, more preferably from about 11.0 to about 12.0 carbon atoms; and wherein said modified unsubstituted alkylbenzene mixture is further characterized by a 2/3-phenyl index of from about 275 to about 10,000, more preferably from about 300 to about 5,000, more preferably still from about 325 to about 2,500, and a 2-methyl-2-phenyl index of less than about 0.3, preferably from 0 to about 0.2, more preferably no more than about 0.1, more preferably still, 0.05 or less.
In another example, the invention includes an enhanced alkylbenzene mixture comprising: I) from 20% to about 99%, (or more, preferably 40% or more, more preferably more than half, e.g., 60% or more, more preferably still 70% or more), by weight of a first alkylbenzene mixture, wherein said first alkylbenzene mixture is said enhanced alkylbenzene mixture and consists essentially of: a) from about 60% to about 25% by weight of a mixture of enhanced alkylbenzenes having formula (I): 
wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and having two methyl termini, and wherein said mixture of enhanced alkylbenzenes contains two or more compounds of said formula (I) differing in molecular weight and wherein said mixture of enhanced alkylbenzenes is characterized by a sum of carbon atoms in R1, R and L of from 9 to 15, preferably from 10 to 14; and an average aliphatic carbon content, based on the sum of R1, L and R2, of from about 10.0 to about 14.0, preferably from about 10.5 to about 12.5, more preferably from about 11.0 to about 12.0 carbon atoms; and further, wherein L has no substituents other than A, R1 and R2; R2 is C1-C3 alkyl (preferably C1-C2 alkyl, more preferably methyl); R2 is selected from H and C1-C3 alkyl (preferably H and C1-C2 alkyl, more preferably H and methyl, more preferably H and methyl provided that in at least about 0.5, more preferably 0.7, more preferably 0.9 to 1.0 mole fraction of said enhanced alkylbenzene sulfonates, R2 is H); A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than L); and b) from about 40% to about 75% by weight (preferably from about 45% to about 65%, more preferably from about 50% to about 60%) of a mixture of modified unsubstituted alkylbenzenes having formula (II): 
wherein A is a (nonsulfonated) benzene moiety (C6H5xe2x80x94 having no substituents other than A) and Y is a linear aliphatic moiety having no substituents other than A consisting of carbon and hydrogen having two methyl termini, and wherein Y has from 9 to 15, preferably from 10 to 14 carbon atoms in total and said mixture of modified unsubstituted alkylbenzenes has an average aliphatic carbon content of from about 10.0 to about 14.0, preferably from about 10.5 to about 12.5, more preferably from about 11.0 to about 12.0 carbon atoms; wherein said first alkylbenzene mixture has a 2/3-phenyl index of from about 275 to about 10,000, more preferably from about 300 to about 5,000, more preferably at least about 325 to about 2,500; and II) the balance, no more than about 80%, (preferably no more than about 60%, more preferably less than half, e.g., no more than about 40%, more preferably still no more than about 25%), by weight of a second alkylbenzene mixture, wherein said second alkylbenzene mixture has a 2/3-phenyl index of from about 75 to about 160 (typical of current commercial LAB); and wherein said enhanced alkylbenzene mixture has an overall 2/3-phenyl index of from about 155 to about 10,000 (preferably from about 170 to about 1200, more preferably from about 180 to about 700).
Other Embodiments
Medium 2/3-Phenyl Surfactant Mixtures
The present invention also encompasses enhanced alkylbenzene sulfonate surfactant mixtures that are more particularly termed xe2x80x9cmedium 2/3-phenyl surfactant mixturesxe2x80x9d. Such mixtures are not the most preferred offered by the invention, but can be very economical.
Thus the invention includes a medium 2/3-phenyl surfactant mixture consisting essentially of: from 1% (preferably at least about 5%, more preferably at least about 10%) to about 60% (in one mode preferably less than about 50%, more preferably less than about 40%), by weight of a first alkylbenzene sulfonate surfactant, wherein said first alkylbenzene sulfonate surfactant is an enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment; and from 40% (in one mode preferably at least about 50%, more preferably at least about 60%) to about 99% (preferably less than about 95%, more preferably less than about 90%), by weight of a second alkylbenzene sulfonate surfactant, wherein said second alkylbenzene sulfonate surfactant is an alkylbenzene sulfonate surfactant mixture other than said enhanced alkylbenzene sulfonate surfactant mixture according to the first embodiment, and wherein said second alkylbenzene sulfonate surfactant has a 2/3-phenyl index of from about 75 to about 160 (typically said second alkylbenzene sulfonate surfactant is a commercial C10-C14 linear alkylbenzene sulfonate surfactant, e.g., DETAL(copyright) process LAS or HF process LAS though in general any commercial linear (LAS) or branched (ABS, TPBS) type can be used); provided that said medium 2/3-phenyl surfactant mixture has a 2/3-phenyl index of from about 160 to about 275 (preferably from about 170 to about 265, more preferably from about 180 to about 255). (of course it is equally possible within the spirit and scope of the invention to prepare any blend of the enhanced alkylbenzene sulfonate surfactant mixture of the invention with any known commercial linear or branched alkylbenzene sulfonate surfactant.
Also included is a detergent composition comprising (preferably consisting essentially of): (a) from about 0.1% to about 95%, by weight (preferably from about 0.5% to about 50%, more preferably from about 1% to about 35%) of medium 2/3-phenyl surfactant mixture as defined supra; (b) from about 0.00001% to about 99.9% (preferably from about 5% to about 98%, more preferably from about 50% to about 95%) of conventional cleaning adjuncts other than surfactants; and (c) from 0% to about 50%, by weight (in some preferred embodiments, 0%, and in others preferably from about 0.1% to about 30%, more typically from about 0.2% to about 10%), of a surfactant other than said medium 2/3-phenyl surfactant mixture; provided that when said detergent composition comprises any other alkylbenzene sulfonate than the alkylbenzene sulfonate of said medium 2/3-phenyl surfactant mixture, said medium 2/3-phenyl surfactant mixture and said other alkylbenzene sulfonate, as a mixture, have an overall 2/3-phenyl index of from about 160 to about 275 (preferably from about 170 to about 265, more preferably from about 180 to about 255).
Likewise part of the invention is a detergent composition comprising: (a) from about 0.1% to about 95%, by weight of medium 2/3-phenyl surfactant mixture as defined supra; (b) from about 0.00001% to about 99.9% of conventional cleaning adjuncts other than surfactants; and (c) from 0.1% to about 50%, by weight of surfactants other than alkylbenzene sulfonates (preferably, one or more surfactants selected from the group consisting of cationic surfactants, anionic surfactants, and anionic surfactants other than alkylbenzene sulfonates, more preferably wherein a cationic surfactant is present at a level of from about 0.2% to about 5%).
Moreover there is included herein a detergent composition consisting essentially of: (a) from about 1% to about 50%, by weight of medium 2/3-phenyl surfactant mixture as defined supra; (b) from about 0.1% to about 98.8% of conventional cleaning adjuncts other than surfactants; (c) from 0.1% to about 50%, by weight of surfactants other than alkylbenzene sulfonates (preferably, one or more surfactants selected from the group consisting of cationic surfactants, anionic surfactants, and anionic surfactants other than alkylbenzene sulfonates, more preferably wherein a cationic surfactant is present at a level of from about 0.2% to about 5%); and (d) from about 0.1% to about 98.8% water.
In additional embodiments of the medium 2/3-phenyl type, there is included a detergent composition consisting essentially of: (a) from about 0.1% to about 95%, preferably from 1% to about 50% by weight of medium 2/3-phenyl surfactant mixture as defined supra; and (b) from about 0.00001% to about 99.9% of conventional cleaning adjuncts other than surfactants.
Processes for preparing a medium 2/3-phenyl surfactant mixture include those comprising a step selected from: (i) blending said first alkylbenzene sulfonate surfactant and said second alkylbenzene sulfonate surfactant; and (ii) blending the nonsulfonated precursor of said first alkylbenzene sulfonate surfactant and the nonsulfonated precursor of said second alkylbenzene sulfonate surfactant and sulfonating said blend.